More Lens Language

Here's a little more I gleaned from Cinematography: Theory and Practice by Blain Brown.

Selective Focus:

Frequently focus is used to highlight certain aspects of a scene. A common use is during dialogue. Combined with an OTS shot (over the shoulder) you highlight the subject, as demonstrated below with a few screenshots from the channel four show Misfits.

Of course the focus can be changed mid shot to highlight any changes. This is known as a rack focus. Here is test of one I found.

Generally speaking the focus puller remembers these points

• Focus goes to the person speaking, you can of course rack back and forth.
• Focus goes to the person facing the camera or most prominent in the frame.
• Focus goes to the person experiencing the most dramatic or emotional moment. This may go against the principle of focusing on the person speaking.
• When in doubt put the focus on the actor with the lower number on the call sheet.